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Letters of Interpretation

PHMSA has published several Frequently Asked Questions (FAQs) documents on programmatic topics. Please review these documents here at: https://www.phmsa.dot.gov/about-phmsa/phmsa-faqs.

Additionally, Office of Hazardous Materials Safety has published Hazardous Materials FAQs based on letters of interpretation on the following topics:

Office of Hazardous Materials Safety: For questions about transporting hazardous materials, needing clarifications of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180), or requesting a formal letter of interpretation, please go to the Hazardous Materials Information Center (HMIC) page for contact information (phone and email address). Pending interpretation letters that are under review by the Office of Hazardous Materials Safety can be found at Pending Hazardous Materials (Hazmat) Interpretations.  

Office of Pipeline Safety: A written regulatory interpretation, response to a question, or an opinion concerning a pipeline safety issue may be obtained by submitting a written request to the Office of Pipeline Safety (PHP–30), PHMSA, U.S. Department of Transportation, 1200 New Jersey Avenue SE., Washington, DC 20590–0001 or at the email address: pipeline_interp_submittal@dot.gov. In addition to email address, the requestor must include his or her return address and should also include a daytime telephone number. Requests should be submitted at least 120 days before the time the requestor needs a response. Note: electronic submission is provided as alternative to the 49 CFR Part 190.11(b) mail-in requirement.

Interpretation letters under review are available at the Office of Pipeline Safety’s Interpretation Review page. To submit comments on an interpretation under review, proceed to the Interpretation Review page, locate the interpretation to comment on, and click the appropriate link to submit a comment on the corresponding interpretation. Comment submissions will be accepted for 30-days after the interpretation letter is posted.

This section of the website below provides the ability to find regulations information including regulations parts, content of sections, and interpretations for regulations sections. A list of parts, identified by the part number and subject is also provided. To browse sections by part, click on the subject link below. You will be taken to the eCFR website to view sections for a part.

The eCFR is also searchable by keyword and other available options on the eCFR website. To search and browse regulations using the eCFR website, use the link below. For assistance, please send an email to PHMSA.Webmaster@dot.gov.

Search the eCFR

Interpretations Reference #

Search Tip: Use quotation marks to search for commonly used phrases, such as “gas transmission” or “cargo tank motor vehicle.”
E.g., 02/09/2021
E.g., 02/09/2021
Ref ID: Date Company Name Individual Name Response Document
10-0077 Thunderbird Cylinder Mr. Fred A. Nachman View
11-0062 DuPont Company Mr. Randolph Martin View
11-0171 Reynolds Transport Mr. Aaron Carr View
11-0179 Hapag-Lloyd (America) Inc. Mr. Matt Krynski Director View
11-0055 Railroad Commission of Texas Mr. James Osterhaus View
11-0133 View
11-0162 Duke Energy Corporation Mr. Chuck Denny View
11-0160 Con-way Freight Ms. Marie Easley-Cook View
11-0127 Veolia Environmental Services Ms. Jennifer Eberle View
11-0175 NitroxFox LLC. Mr. John Fox View
11-0076 Con-way Freight Mr. Keith Jesse Powell View
11-0163 International Radiation Safety Consulting, Inc. Mr. Sean Chapel View
10-0213 Thunderbird Cylinder, Inc Mr. Fred Nachman View
11-0131 Flightpath Services, Inc. Mr. Douglas Svoboda View
11-0173 Department of the Army- SDDC Mr. Daniel A. Maham View
11-0161 Young & Franklin Inc. Mr. Greg Michalowski View
11-0061 Ventura Transfer Company Mr. Jim Cheney View
11-0145 Riceland Foods, Inc. Mr. Neil Washburn View
11-0135 Veolia Environmental Services Ms. Jennifer Eberle View
10-0134 Conax Florida Corporation Cobham Life Support Mr. Thanh Seybold View
11-0143 ICC Nexergy Mr. David Brongiel View
11-0151 National Aquatic Service, Inc. Mr. Michael Druce View
11-0040 U.S. Department of Energy Office of Packaging and Transportation Mr. James M. Shuler Manag View
10-0257 Thompson Hine LLP Mr. Jason Tutrone View
11-0106 The Jet Companies Mr. Mark Ellery View
11-0063 Con-Way Freight Mr. Michael Gardner View
11-0073 International Titanium Powder Mr. Bill Murphy er View
11-0124 SiGNa Chemistry Mr. Michael Lefenfeld View
11-0116 Land O"Lakes Purina Feed, LLC Mr. Paul A. Luther, P.E. View
11-0039 LAN CARGO Mr. Carlos Ferriol View
11-0085 Triumvirate Environmental Mr. Thomas Goss View
11-0150 Holland & Knight LLP Mr. Jonathan Epstein View
11-0141 Kajuligan Corporation Mr. Clifford Croft View
11-0122 Safety Management Services Inc. Mr. A. Garn Butcher View
11-0169 Duke Energy Corporation Mr. Charles Denny View
PI-11-0005 Sabco Oil and Gas Corporation Mr. Max Jameson View
11-0152 FedEx Express Mr. Thomas (TJ) Leech, III, View
11-0066 Boyle Transportation Mr. Rick Araniz View
11-0104 Transport Canada, Ontario Region Mr. Jasbir Grover View
11-0136 Recology San Francisco Mr. Billy Puk View
11-0112 Midstate Air Freight and Logistics, Inc., DBA Callahan Air Expediters Mr. Jeremy K. Nantz View
11-0016 AllTransPack, Inc. Mr. Hank Baird . View
10-0247 View
11-0020 Department of the Air Force Ms. Robbin L. Miller View
10-0128R Aleris International, Inc Mr. Kenneth J. Willings View
11-0108 Mr. Tae Kim View
PI-10-0024 XTO Energy, Inc. Ms. Alice Ratcliffe View
PI-11-0004 Mississippi Public Service Commission Mr. Mark McCarver View
11-0053 Department of the Army Mr. Joseph Dugan View
11-0060 National Electrical Manufacturers Association Mr. Craig Updyke View